1. Field of the Invention
The present invention relates to a complex machine comprising a host computer such as a computer, a word processor, or an image editor; an image duplicator combined with an automatic document feeder; and a low-speed laser printer provided for the host computer.
2. Description of the Prior Art
A laser printer has been conventionally used widely as an output unit of an image editor or the like to form and edit a drawing on a word processor or a CRT display because of its capability of providing an extremely clear image. However, such a laser printer used as an output unit of a word processor or the like is generally a compact type device having a relatively low processing speed capable of printing five or six sheets per minute. This is because any document formed by means of a word processor or the like is generally small in volume seldom exceeding several hundred pages, and therefore requiring not so much time for the printing process. Another reason is that a high-speed laser printer is much more expensive as compared with a word processor or the like. Therefore, when a great amount of copies of a document formed by a word processor is necessary, there have been required such troublesome procedures that firstly an original sheet is formed by means of a word processor and then a necessary amount of copies are duplicated by means of a high-speed duplicating machine.
In view of the above-mentioned problems, there was conventionally proposed a complex machine having a printer combined with a duplicator as disclosed in the Japanese Utility Model Publication 62-2616 in which each original sheet formed by the printer is transferred onto the original sheet glass table of the duplicator and then the image of the original sheet is duplicated onto a duplication sheet by the duplicator.
However, in a compact low-speed laser printer used as an output unit of a word processor or the like, there is usually provided only one sheet supply section, and when it is required to change the sheet size, the sheet supply cassette or the sheet stored in the sheet supply cassette is to be changed. Therefore, when such a compact low-speed printer is used for the above-mentioned complex machine, there has been required troublesome procedures of confirming whether a sheet of a desired size is set up in the printer. Particularly when putting the space utility and other factors of an office into consideration, it is likely that a complex machine combining a duplicator and a printer is to be installed in a space which has been occupied by a conventional duplicating machine. The above fact means that the word processor is usually placed apart from the printer. Therefore, in a printing process, it has been required for the operator to take the troublesome actions of moving apart from the operating position of the word processor or the like to confirm whether a sheet of the desired size is set up in the sheet supply section of the laser printer.
There was conventionally proposed another complex machine in the Japanese Paten Laid-Open 61-176967 in which the printer and the duplicator are integrally combined in a common frame and each original sheet printed in the printer section is transferred onto the original sheet glass table to be subject to a duplicating process through an exposure process in the duplicator section. In the above integrated type complex machine, since a sheet supply section can be used commonly for the printer section and duplicator section, therefore even when no sheet of the desired size is in the printer section, a sheet of the desired size can be supplied from the sheet supply section provided in the duplicator.
However, in a complex machine having a printer and a duplicator combined in an integrated form, the printer section and the duplicator section must be controlled independently without any interlock operation in order to put the printing process of the printer section and the duplicating process of the duplicator section into operation at the same time, which also requires an extremely complicated design of the drive and control systems. In other words, it has been practically very difficult to put the duplicating process of the duplicator section into operation while carrying out the printing process of the printer section.
Furthermore, in the above-mentioned type of the complex machine, it is highly possible that the printing command for the printer is input independently without regard to the operating condition of the duplicator. In more detail, it can be assumed that the above-mentioned complex machine is to be installed in the place where a conventional duplicating machine has been placed apart from a word processor or the like device to give a printing command to the printer in consideration of the space utility of the office. Therefore, the operator of the word processor or the like cannot judge whether the duplicator is in operation, i.e., it is highly possible that the operator executes the printing process without confirming whether the duplicator is in operation.
If it is assumed that a printing command is given to the printer at the time the duplicator is in operation, the duplicating process of the duplicator is compulsorily interrupted to proceed into a printing process of the printer, the operator of the duplicator suffers serious inconvenience. Particularly, since the compact laser printer has a low printing speed, the operator of the duplicator must wait for a long time.
If it is assumed on the contrary that the printing process is to be compulsorily interrupted until the duplicating process of the duplicator is completed, the operator of the printer suffers inconvenience.